KVM does not have the means to support enabling the rva22u64 profile.
The main reasons are:

- we're missing support for some mandatory rva22u64 extensions in the
  KVM module;

- we can't make promises about enabling a profile since it all depends
  on host support in the end.

We'll revisit this decision in the future if needed. For now mark the
'rva22u64' profile as unavailable when running a KVM CPU:

$ qemu-system-riscv64 -machine virt,accel=kvm -cpu rv64,rva22u64=true
qemu-system-riscv64: can't apply global rv64-riscv-cpu.rva22u64=true:
    'rva22u64' is not available with KVM

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
---
 target/riscv/kvm/kvm-cpu.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/target/riscv/kvm/kvm-cpu.c b/target/riscv/kvm/kvm-cpu.c
index c6615cb807..5f563b83df 100644
--- a/target/riscv/kvm/kvm-cpu.c
+++ b/target/riscv/kvm/kvm-cpu.c
@@ -358,7 +358,7 @@ static void cpu_set_cfg_unavailable(Object *obj, Visitor *v,
     }
 
     if (value) {
-        error_setg(errp, "extension %s is not available with KVM",
+        error_setg(errp, "'%s' is not available with KVM",
                    propname);
     }
 }
@@ -438,6 +438,11 @@ static void kvm_riscv_add_cpu_user_properties(Object *cpu_obj)
     riscv_cpu_add_kvm_unavail_prop_array(cpu_obj, riscv_cpu_extensions);
     riscv_cpu_add_kvm_unavail_prop_array(cpu_obj, riscv_cpu_vendor_exts);
     riscv_cpu_add_kvm_unavail_prop_array(cpu_obj, riscv_cpu_experimental_exts);
+
+   /* We don't have the needed KVM support for profiles */
+    for (i = 0; riscv_profiles[i] != NULL; i++) {
+        riscv_cpu_add_kvm_unavail_prop(cpu_obj, riscv_profiles[i]->name);
+    }
 }
 
 static int kvm_riscv_get_regs_core(CPUState *cs)
-- 
2.41.0

On Fri, Oct 6, 2023 at 11:24 PM Daniel Henrique Barboza
<dbarboza@ventanamicro.com> wrote:
>
> KVM does not have the means to support enabling the rva22u64 profile.
> The main reasons are:
>
> - we're missing support for some mandatory rva22u64 extensions in the
>   KVM module;
>
> - we can't make promises about enabling a profile since it all depends
>   on host support in the end.
>
> We'll revisit this decision in the future if needed. For now mark the
> 'rva22u64' profile as unavailable when running a KVM CPU:
>
> $ qemu-system-riscv64 -machine virt,accel=kvm -cpu rv64,rva22u64=true
> qemu-system-riscv64: can't apply global rv64-riscv-cpu.rva22u64=true:
>     'rva22u64' is not available with KVM
>
> Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  target/riscv/kvm/kvm-cpu.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/target/riscv/kvm/kvm-cpu.c b/target/riscv/kvm/kvm-cpu.c
> index c6615cb807..5f563b83df 100644
> --- a/target/riscv/kvm/kvm-cpu.c
> +++ b/target/riscv/kvm/kvm-cpu.c
> @@ -358,7 +358,7 @@ static void cpu_set_cfg_unavailable(Object *obj, Visitor *v,
>      }
>
>      if (value) {
> -        error_setg(errp, "extension %s is not available with KVM",
> +        error_setg(errp, "'%s' is not available with KVM",
>                     propname);
>      }
>  }
> @@ -438,6 +438,11 @@ static void kvm_riscv_add_cpu_user_properties(Object *cpu_obj)
>      riscv_cpu_add_kvm_unavail_prop_array(cpu_obj, riscv_cpu_extensions);
>      riscv_cpu_add_kvm_unavail_prop_array(cpu_obj, riscv_cpu_vendor_exts);
>      riscv_cpu_add_kvm_unavail_prop_array(cpu_obj, riscv_cpu_experimental_exts);
> +
> +   /* We don't have the needed KVM support for profiles */
> +    for (i = 0; riscv_profiles[i] != NULL; i++) {
> +        riscv_cpu_add_kvm_unavail_prop(cpu_obj, riscv_profiles[i]->name);
> +    }
>  }
>
>  static int kvm_riscv_get_regs_core(CPUState *cs)
> --
> 2.41.0
>
>